<script src="vue.js"></script>

<div id="app">
    <p>{{msg}}</p>
</div>

<script>
    var vue=new Vue({
        el:'#app',
        data:{
            msg:"我又回来了"
        },
        mounted(){
            console.log("页面挂载之后")
            console.log(this.$el.innerHTML)
        },
        beforeMount(){
            console.log("页面挂载之前")
            console.log(this.$el.innerHTML)
        }
    })
</script>